Because of their structural efficiency, certain forms of structures are preferred where considerations of size, weight and transportability are important. Among these are truss structures, which have a high stiffness-to-weight ratio and a simple, self-determined geometry. Since the size of these structures precludes their transport over long distances, minimum packing volume and weight are important factors.
Among the requirements that govern the design of such structures is the use of components that can be easily handled with a minimum amount of labor and effort. However, structures which comply with this requirement by automatically unfolding and positioning themselves in a gravity-free environment are generally not efficient and carry a weight penalty because of the self-deployment feature. Additionally, it is desirable that the methods and the apparatus used for construction and disassembly be both simple and automated to the maximum possible extent in order to minimize the requirement for human intervention. However, structures which are capable of automated construction at a remote site often fail to achieve the necessary stiffness-to-weight ratio, stowage efficiency and the requisite simplicity of the method and apparatus used for assembly. Also, while it would otherwise be preferred, existing structures of the type discussed are typically incapable of construction and disassembly at a single general location and require the equipment in use, as well as construction performed, to move along the structure as the latter grows or diminishes in size during assembly or disassembly respectively.
By way of example, U.S. Pat. No. 4,259,821 to Bush discloses a truss structure, formed from structural columns, which does not lend itself to an automated assembly method because of its complexity. U.S. Pat. No. 4,337,560 to Slysh discloses a structure that lends itself to an automated assembly technique. However, such a structure is not capable of being constructed from a single general location and it requires an assembler trolley which crawls along the structure as the structure is built up during construction.